ABSTRACT We describe the identification of Methylobacterium zatmanii as the causative agent of bacteremia and fever in an immunocompromised patient. The patient, a 60-year-old man, had a 5-month history of acute myeloid leukemia and had been on chemotherapy throughout this period. Seven days after the onset of neutropenia, the patient developed fever. The combination of ciprofloxacin, co-trimoxazole, imipenem, amikacin, and vancomycin led to a complete defervescence. On subculture from six positive blood cultures, the organism grew only on buffered charcoal yeast extract agar and not on standard agars. Identification by universal PCR and subsequent sequence analysis of the amplified 16S rRNA gene segment was achieved. This identification by molecular biology techniques was confirmed by conventional biochemical tests. To our knowledge, this is the first description of M. zatmanii isolated from patient material.